Mobile communication networks include a core network, which is operated by a mobile network operator and comprises network components for providing mobile services, such as services for speech and/or data connections. Mobile communication devices access the core network through a radio access network which is connected to the core network. The radio access network provides the radio technology for establishing wireless connections between mobile communication devices and the mobile communication network. It is configured as a cellular network comprising a plurality of radio cells and each radio cell is served by a base station system of the radio access network.
Usually, each core network operator provides his own radio access network for providing access to the operator's core network. However, the deployment of a radio access network involves high efforts and costs. Therefore, it has been proposed that core network operators share a common radio access network. In view of the Universal Mobile Telecommunications System (UMTS), configurations and procedures for shared radio access networks are described in the document TS 23.251 (version 9.2.0) of the 3rd Generation Partnership Project (3GPP). In a shared radio access network, the base station systems are connected to multiple core networks and have to route user data and signaling messages from mobile communication device to the correct core network, i.e. the core network the mobile communication device is registered in or—in the registration process—the core network in which the mobile communication wishes to register.
According to TS 23.251, a base station system of a shared radio access network includes in the broadcast system information broadcasted in the radio cells or cells served by the base station system the PLMN-IDs of the associated core networks. A mobile communication device takes the broadcasted PLMN-IDs into account in the PLMN selection process. Furthermore, the mobile communication device informs the base station system, which core network is selected, so that the base station system is enabled to route signaling messages and user data received from the mobile communication to the selected core network. The information is given in the Radio Resource Control (RRC) signalling which refers to the radio connection between the mobile communication device and the base station system. Thus, it is the base station system which has to assign the information which core network has been selected to the higher layer messages, which are transmitted from a mobile communication device to a core network via the base station system.
Exemplary embodiments of the subject innovation may allow for an easier routing of messages to a core network in a base station system of a shared radio access network connected to multiple core networks.